All living things - bacteria, fungi, plants, animals and
other organisms - have evolved to live in specific areas
on the Earth. Local climate, geology, soils, available
water and other natural factors influence which plants and
animals live in particular ecosystems and habitats.

Natural areas are wild to semi-wild areas such as fields,
forests, streams and wetlands, that are composed of
diverse groups of native plants, animals and
microorganisms. These biological groupings have evolved
over thousands of years into natural communities and
ecosystems. Large to small natural areas are all around us
and include parks, refuges, preserves, fields, forests,
open spaces, undeveloped areas on community and corporate
lands, schoolyards, municipal facilities and backyard
habitats.

What are native species?
A native species is one that occurs naturally in a
particular place without human intervention. Species
native to North America are generally recognized as those
occurring on the continent prior to European settlement.
Non-native plants are species that have been introduced to
an area by people from other continents, states,
ecosystems and habitats. Many non-native plants have great
economic value for agriculture, forestry, horticulture and
other industries and pose little to no threat to our
natural ecosystems. Others have become invasive and pose a
serious ecological threat.

What are invasive plants?
Invasive plants reproduce rapidly, spread over large areas
of the landscape and have few, if any, natural controls,
such as herbivores and diseases, to keep them in check.
Many invasive plants share some important characteristics
that allow them to grow out of control. These include: (1)
spreading aggressively by runners or rhizomes; (2)
producing large numbers of seeds that survive to
germinate; and (3) dispersing seeds away from the parent
plant through various means such as wind, water, wildlife
and people.

How are invasive plants introduced?
People introduce exotic plants to new areas, on purpose
and by accident, through a variety of means. Some species
are introduced for use in gardening and landscaping, or
for erosion control, forage and other purposes. For
instance, in the 1930s, the Civilian Conservation Corps
planted kudzu vine (introduced from Japan), throughout the
Southeast to help stabilize soil in erodible areas. Kudzu
grew so prolifically that it was nicknamed the "vine
that ate the South." Others come in unknowingly, on
various imported products or in soil, water and other
materials used for ship ballast. Many invasive aquatic
plants are introduced by dumping unwanted aquarium plants
into waterways. Once established in a new environment,
some exotic species proliferate and expand over large
areas, becoming invasive pests.

How do invasive plants spread?
Invasive plants spread by seed, vegetative growth
(producing new plants from rhizomes, shoots, tubers etc.)
or both. Seeds, roots and other plant fragments are often
dispersed by wind, water and wildlife. Animals spread
invasive plants by consuming fruits and depositing seeds
as well as transporting seeds on their feet and fur.
People also help spread invasive plants by carrying seeds
and other plant parts on shoes, clothing and equipment and
using contaminated fill dirt and mulch. Invasive aquatic
plants are often spread when plant parts attach to boat
anchors and propellers.

Why are invasive plants a problem in natural
areas?
Like an invading army, invasive plants are taking over and
degrading natural ecosystems. Invasive plants disrupt the
intricate web of life for plants, animals and
microorganisms and compete for limited natural resources.
Invasive plants impact nature in many ways including
growing and spreading rapidly over large areas, displacing
native plants, including some very rare species, reducing
food and shelter for native wildlife, eliminating host
plants of native insects and competing for native plant
pollinators. Some invasives spread so rapidly that they
muscle out most other plants, changing a forest, meadow,
or wetland into a landscape dominated by one species. Such
"monocultures" (stands of a single plant
species) have little ecological value and greatly reduce
the natural biological diversity of an area.

Invasive plants also affect the type of recreational
activities that we can enjoy in natural areas such as
boating, bird watching, fishing and exploring. Some
invasives become so thick that it is impossible to access
waterways, forests and other areas. Once established,
invasive plants require enormous amounts of time, labor
and money to control or eliminate. Invasive species cost
the United States an estimated $34.7 billion each year in
control efforts and agricultural losses.

How to prevent spread of invasive plants
Become familiar with invasive plant species in your area.
When selecting plants for landscaping, avoid using known
invasive species and those exotic species exhibiting
invasive qualities. A few common ornamental plants that
show invasive tendencies and that have become problematic
elsewhere in the U.S. include: pampas grass (Cortaderia
selloana); jubata grass (Cortaderia jubata);
fountaingrass (Pennisetum setaceum); Chinese
fountaingrass (Pennisetum alopecuroides);
star-of-Bethlehem (Ornithogalum umbellatum);
creeping lilyturf (Liriope spicatum) and water
hyacinth (Eichhornia crassipes). Ask for native
plant alternatives at your nursery. Obtain a list of
plants native to your state from your native plant
society, state natural resources agency, or the U.S. Fish
and Wildlife Service, Chesapeake Bay Field Office (see
references). Carry this list with you to nurseries to
help with plant selection.

If you already have invasives planted on your property,
consider removing them and replacing them with native
species, such as those suggested in this guide. Refer to
reputable resources (see
references) for more information on identifying
invasive plants and the best ways to control or remove a
specific plant. When visiting a natural area, be alert for
invasive species. If you see some, notify the agency or
organization responsible for managing the land. Before you
leave, avoid carrying "hitchhiking" plant
material by taking time to brush seeds from clothing and
shoes and remove plant material from boats, trailers and
other items.

Information about this guide
This illustrated handbook describes a variety of highly
invasive plants impacting the region's natural areas.
It provides identification tips, a few suggested native
plant alternatives and some control information for a
variety of invasive aquatic and terrestrial species in the
mid-Atlantic region.

For purposes of this manual, the mid-Atlantic region
includes the District of Columbia and the states of
Delaware, Maryland, New Jersey, Pennsylvania, Virginia and
West Virginia. More than 200 exotic plant species have
been identified by natural resource managers as
problematic invaders of natural areas in the mid-Atlantic
region. The plants included in this guide are some of the
most problematic invasives that are responsible for
significant degradation of natural communities in this
region. This guide is not intended to be a complete
resource on invasive plants in the mid-Atlantic region and
a list of organizations is provided where readers can
obtain additional information. Plants excluded from this
guide should not be assumed to be environmentally safe.

For more complete information on invasive plants,
including species not covered in this guide, contact the
Mid-Atlantic Exotic Pest Plant Council at
http://www.ma-eppc.org or the Plant Conservation Alliance,
Alien Plant Working Group at
http://www.nps.gov/plants/alien/.